A good place for this question is on the IB discussion forum: http://www.interactivebrokers.com/cgi-bin/discus/discus.pl
SSF's will be as simple as point and click. Assuming there is a tight liquid market (and this could be a big assumption), you can point click and have sold a stock on a downtick within milliseconds. Margin on the SSF's from a commodities account wil be 5:1 which are more benefical than securities. You'll also save on commissions. For those with commodity accounts under 25K, the main benefit is that you'll be able to avoid the PDT restrictions. You made a request about IB. Initial indications from the SEC were that they "frown" upon their use. We're going to wait and see how liquid the SSF's turn out before doing any more work on them.